3-46 Keysight N5241A/42A/49A Service GuideTests and AdjustmentsPerformance Tests3-11.This test is repeated for the 15 and 30 dB noise gain settings.If the Analyzer Fails this Test:A failure of this test indicates a fault in the noise receiver chain. This canindicate a faulty assembly or a loose cable.— Check for proper torquing of all semi-rigid cables in the receiver chain, andthen repeat this test.— If the analyzer still fails this test, replace the A7 Noise Receiver board andrepeat this test. Refer to “Removing and Replacing the A4–A13 Boards (Foranalyzers with serial numbers prefixed MY/SG/US5150 and below.)” onpage 7-14 or “Removing and Replacing the A4–A13 Boards (For analyzerswith serial numbers prefixed MY/SG/US5201 and above.)” on page 7-17.Noise Receiver Compression TestFunction of the Test: To measure the PNA-X noise receiver compression at thereceiver’s specified maximum input power level.Specification Tested: Test Port Input: Option 029 – Noise Receiver Input RangeEquipment Used:— Powermeter— Powersensors— Testcables— 10 dB attenuatorDescription of the Test:The noise receiver compression level varies from -16 dBm for the high band ofthe low gain stage down to -52 dBm for the low band of the high gain stage.This range is too wide to get an accurate source power calibration for eachgain stage using a standard power sensor. So the source power is calibrated ata higher power level, and the analyzer’s st andard receiver is used to accuratelymeasure the effect of the added source attenuation which is needed to bringthe source power down to the compression level.To ensure that the match between the analyzer source and receiver is optimalfor the most accurate measurements, an external 10 dB attenuator is used.1. The analyzer is Preset.2. A test cable is attached to Port 1 with a 10 dB attenuator at the end of thecable.3. Using the low frequency power sensor, a source power calibration isperformed at the end of the cable for dozens of frequency points. Thepower level is set between -9 and -18 dBm, at a multiple of 10 dB abovethe specified compression level.
